In the manufacturing and processing of mass-produced articles in the consumer goods industry, there is generally used a plurality of processing systems and/or machines in series. The individual articles, such as glasses, bottles, cans, boxes, etc., move from one processing station to the next on conveyor belts. On such conveyor belts, the articles are generally already separated and stand one behind the other, but their spacing is extremely non-uniform. This non-uniform spacing is prejudicial to the requirement that the articles be supplied synchronously to the further processing station, that is to say with an identical spacing, because production sequences or treatment processes in the individual machines are usually accomplished during uniform time cycles which translate into uniform cyclic spacing distances along the moving line. Therefore, the articles must be supplied individually in accordance with the required cyclic spacing, which, of course, must be greater than the article diameter along the line. The transfer to and from the conveyor belts or machine mechanisms causes serious problems arising from different article shapes and different processing speeds, which problems make the complete production sequence more fault-prone.
In order to at least partly control these problems, it is common to use an apparatus of the above-described type with a feed screw as an essential component. The articles are taken up by this feed screw, are separated by the increasing spacing course, and then transferred at uniform time intervals to the production machine. In spite of the fact that this system is used in almost all production processes, it cannot be considered ideal.
As the screw takes up the article and transports it, the point of engagement of the article must be very precisely determined, particularly with tall and small diameter articles, so that the article is not overturned. This is particularly the case at high speeds and when articles arrive singly. The reason for this is that due to the special characteristics of the screw design, an article which is supplied in an irregular manner can be struck in such a way by the beginning thread of the screw helix that the article is jerked abruptly which in the case of high, small diameter products generally leads to wobbling, overturning, and consequent interruption of the entire production sequence. In the case of flat, large diameter articles, a screw cannot be used, because the large screw diameter required for handling the articles exceeds the article height, so that the screw rotation axis would be located above the product height. Articles with complicated configurations can often not be gripped at the ideal contact point by the screw. This can lead to a passing under or knocking down of the article. Furthermore, when a feed screw is dirty or worn, the constant abrasion of the articles by it can lead to scratches or damage to the articles. This applies particularly in the case of labelled or bright objects. In the case of thin or elastic articles which are not supplied in a regular manner, deformation or damage can be caused by the advancing start of the screw. It is also disadvantageous that at high production speeds the advancing first thread of the feed screw momentarily acts as a barrier, so that individually fed-in articles cannot be picked up, and it is only after the build up of a so-called backlog or a dynamic pressure that the articles can be taken up by the screw. Since, as stated, this problem occurs particularly at high production speeds, each article strikes a stationary column of articles at high speed. This is particularly disadvantageous in glassworks, due to the danger of breakage. Experience in glassworks has shown that all forms of impacts, scratches, etc. occurring just after manufacture reduce the strength of the glasses to a considerable extent. Finally, it is disadvantageous that different screws have to be fitted for different diameters and heights of the articles handled.
It is also known to separate and to synchronously transfer individual articles by means of a feed star. However, even this relatively much-used system has significant disadvantages. For example, the distribution of small-diameter articles over large distances is not possible. In addition, at high speed the star ends act as a wall and lead to the overturning of individually arriving articles, or even to a jamming of them between the star and facing guide wall.
It has also been proposed to separate articles by means of belts moving at a higher speed than the conveyor belt and which thus spread the articles apart. However, this system has the disadvantage that non-uniform spacings of the fed articles still remain non-uniform.